Rotary pump



L. R. CASEY ROTARY PUMP July 18, 1967 Filed May 26, 1965 2. 1 7 9 I Z A. I 5 F 1 1 22! A?) v\ w v 3 3 3 5% V m fi i w 1 4 7 Q I w! 1| 5 w Q M i 4 j n of Z.

0 mw mm" m mNn v 0R mp. mm M i w 9 w w A vm United States Patent 3,331,326 ROTARY PUMP Leonard R. Casey, 2422 E. th Place, Tulsa, Okla. 74104 Filed May 26, 1965, Ser. No. 459,056 2 Claims. (Cl. 1032) The present invention relates to rotary pumps.

When pumps are referred to in the present specification, it is to be understood that compressors are also comprehended. This invention is equally adaptable to the pumping of liquids and the compression of vapors.

It is an object of the present invention to provide a rotary pump which has a smooth pumping action without pulsing.

Another object of the present invention is the provision of a rotary pump which operates at relatively low noise level.

Finally, it is an object of the present invention to provide a rotary pump which will :be relatively simple and inexpensive to manufacture, easy to assemble, install, maintain and repair, and rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a view in cross section of a rotary pump according to the present invention;

FIGURE 2 is a cross-sectional view of a pump according to the present invention, taken in a plane which includes the axis of the rotor;

FIGURE 3 is a view similar to FIG. 1 but with the rotor removed; and

FIGURE 4 is a view of the rotor.

Referring now to the drawing in greater detail, there is shown a rotary pump having a casing 1 of generally flattened cylindrical shape. Casing 1 is comprised of a pair of roughly circular plates 3 and 5 which are detachably secured together. Plate 5 has a peripheral flange that extends toward and spaces plate 3 away from the major portion of plate 5, whereby to provide between plates 3 and 5 a rotor chamber.

A pump rotor 7 is mounted for rotation in the casing 1, in the chamber between plates 3 and 5. Rotor 7 is rotatable by means of an axialshaft 9 that extends through hearings in plate 5. Rotor 7 also has a bearing boss that is rotatably received in plate 3. Shaft 9 is driven by power means such as an electric motor (not shown) to rotate rotor 7 and drive the pump.

The periphery of the chamber of easing 1 is provided with a pair of diametrically opposed inlets 11 and 13 for the fluid to be pumped, and a pair of diametrically opposed outlets 15 and 17 for the pumped fluid. Inlet 11 and outlet 15 are disposed closely adjacent each other, while inlet 13 and outlet 17 are disposed closely adjacent each other on the opposite side of easing 1.

Rotor 7 has a cylindrical outer periphery characterized by a plurality of radially extending bores 19 that open therethrough. In each bore, there is mounted a piston 21 for radial reciprocatory sliding movement. The side walls of each bore 19 are pierced by radially extending slots 23 on opposite sides of rotor 7.

Each of plates 3 and 5 is provided with an oval groove 25 that opens into the cavity of casing 1. The two grooves 25 are exactly congruent and precisely aligned on opposite sides of easing 1. They open toward each other. Although the grooves 25 are thus broadly characterized as oval, they are preferably elliptical, and concentric with rotor 7. Preferably, the major axes of the ellipses of both grooves 25 lie in a common plane which passes midway between inlet 11 and outlet 15 on the one hand, and inlet 13 and outlet 17 on the other hand. Preferably, the minor axes of the ellipses of both grooves 25 lie in a common plane which is angularly spaced midway between inlet 11 and outlet 17 on the one hand, and inlet 13 and outlet 15 on the other hand. In other Words, the pump is preferably bisymmetric about the horizontal plane seen in FIG. 1 that includes the axis of rotor 7, and also about the vertical plane in FIG. 1 that includes the axis of rotor 7.

Each piston 21 carries a wristpin 27 that extends therethrough and is perpendicular to the axis of the piston. Preferably, the axis of the wristpin also intersects the axis of the piston. Wristpins 27 extend outwardly substantial distances on either side of pistons 21, and extend through slots 23 and terminate in grooves 25. Upon rotation of rotor 7, therefore, Wristpins 27 ride in grooves 25 and confine movement of pistons 21 to movement along an oval path, and preferably an elliptical path. The path of rotor 7 being circular, it will of course be understood that pistons 21 are thus caused to reciprocate in bores 19, through two complete cycles of reciprocation for each revolution of rotor 7. It will of course also be understood that the ends of Wristpins 27 need not be plain as shown, but can be provided with any desired antifriction devices such as roller bearings or the like (not shown). By the same token, it goes without saying that the bearing of shaft 9 of rotor 7 in plates 3 and 5 can be of any desired antifriction type.

The inner periphery of the chamber within casing 1 is characterized by the provision of four lands 29, 31, 33 and 35, equally peripherally spaced about the interior of the chamber, that is, spaced apart. Also, the lands are each 'bi-sected 'by the major and minor axes of the ellipses of grooves 25. Each land is of substantially less than 45 in peripheral extent, however, so that the spaces left between the lands are substantially greater than 45 in peripheral extent. The inner peripheral surface of each land lies on an imaginary cylinder that substantially coincides with the outer cylindrical surface of rotor 7, so that the outer cylindrical periphery of rotor 7 is in slidable sealing contact with each of the four lands at all times.

Lands 29, 31, 33 and 35 thus segregate the interior of casing 1 outside rotor 7 into four separate compartments each of which communicates with one of inlets 11 and 13 and outlets 15 and 17. There is thus an inlet chamber 37 within the casing between lands 29 and 31 and disposed peripherally outwardly of rotor 7 and in fluid communication with inlet 11; there is an outlet chamber 39 between lands 31 and 33 peripherally outwardly of rotor 7 and in communication with outlet 17; there is an inlet chamber 41 between lands 33 and 35 peripherally outwardly of rotor 7 and in communication with inlet 13; and there is an outlet chamber 43 between lands 35 and 29 peripherally outwardly of rotor 7 and in communication with outlet 15.

In operation, the rotation of rotor 7 causes pistons '21 to reciprocate in bores 19 along paths that ensure that fluid will be simultaneously drawn into both inlets 11 and 13 and simultaneously expelled from both outlets 15 and 17 Following the operation of a representative piston, for example that which is at the three oclock position in FIG. 1, it will be recognized that as rotor 7 turns clockwise as seen in FIG. 1, that piston, which initially is substantially in contact with land 33, will be retracted into its bore 19 as it moves through the four oclock and five ocl-ock positions. This retraction of the piston into its bore over this portion of the path of the rotor will effectively enlarge the inlet chamber 41 so that fluid will be drawn in through inlet 13. As this piston passes the six oclock position, its bore 19 slides over the land 35, so that thereafter, that piston will have no influence on the inlet chamber 41. Instead, as the piston now enters the seven and eight oclock positions, it will advance radially outwardly in its bore 19, thereby elfectively to decrease the volume of the outlet chamber 43 thereby to expel fluid from outlet 15. The piston in its nine oclock position then passes over land 29, by which it is sealed from further influence on outlet chamber 43, and then enters int-o fluid communication with the inlet chamber 37, into which it draws fluid through inlet 11 as the piston moves through its ten and 11 oclock position. In its 12 oclock position, the piston is sealed from inlet chamber 37 by land 31, whereafter it revolves into communication with outlet chamber 39 in its one and two oclock positions, expelling fluid from chamber 39 through outlet 17.

It will thus be recognized that the inlets and outlets 11-17 can be positioned at any desired peripheral location in communication with their respective inlet or outlet chambers 37-43, depending on convenience of location.

Needless to say, rotation of rotor 7 in the opposite direction exactly reverses the operation of the device and causes the inlet and outlet chambers to function instead as outlet and inlet chambers, respectively.

From a consideration of the foregoing disclosure, therefore, it will be evident that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been disclosed and illustrated in connection with a preferred embodiment, it

is to be understood that modifications and variations may be resorted to without departing from the spirit of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

Having described my invention, I claim:

1. A rotary pump comprising a casing comprising a pair of plates, a shaft rotatable in the casing, a rotatable cylinder in unitary assembly with and extending radially outwardly from the shaft between the plates, the casing having a pair of inlets on opposite sides of the cylinder, the casing having a pair of outlets on opposite sides of the cylinder, a plurality of radially extending bores opening through the outer periphery of the cylinder, a piston slidably disposed in each bore, the casing plates on opposite sides of the cylinder having opposed confronting congruent oval grooves, the cylinder having radially extending slots therethrough on each side of each said bore, and wristpins secured to each said piston and passing through both slots of each bore and terminating in both said oval grooves to guide the pistons in an oval path upon rotation of the cylinder.

2. A rotary pump comprising a casing, a rotor rotatable in the casing, the casing having a pair of inlets on opposite sides of the rotor, the casing having a pair of outlets on opposite sides of the rotor, a plurality of radially extending bores opening through the outer periphery of the rotor, a piston slidably disposed in each bore, opposed cam grooves guiding the pistons in an oval path upon rotation of the rotor, the casing being spaced radially outwardly of the rotor over most of the periphery of the rotor, the casing having four peripherally spaced sealing lands in sealing contact with the rotor, each said land being of substantially less peripheral extent than the space between the lands, the major and minor axes of said oval path passing through all four said lands and lying midway between each adjacent pair of inlets and outlets, said lands being equally peripherally spaced apart, there being an inlet and an outlet disposed closely adjacent each other in a pair on opposite sides of said major axis substantially closer to said major axis than to said minor axis, there being two said pairs one diametrically opposed to the other, the axes of the inlet and outlet of each said pair being parallel to each other.

References Cited UNITED STATES PATENTS 1,332,516 3/1920 ODonnell 103-161 2,430,362 11/1947 Parine 103-161 ROBERT M. WALKER, Primary Examiner.

MARK M. NEWMAN, Examiner.

W. J. KRAUSS, Assistant Examiner. 

1. A ROTARY PUMP COMPRISING A CASING COMPRISING A PAIR OF PLATES, A SHAFT ROTATABLE IN THE CASING, A ROTATABLE CYLINDER IN UNITARY ASSEMBLY WITH AND EXTENDING RADIALLY OUTWARDLY FROM THE SHAFT BETWEEN THE PLATES, THE CASING HAVING A PAIR OF INLETS ON OPPOSITE SIDES OF THE CYLINDER, THE CASING HAVING A PAIR OF OUTLETS ON OPPOSITE SIDES OF THE CYLINDER, A PLURALITY OF RADIALLY EXTENDING BORES OPENING THROUGH THE OUTER PERIPHERY OF THE CYLINDER, A PISTON SLIDABLY DISPOSED IN EACH BORE, THE CASING PLATES ON OPPO- 